Didymo threat closes famous springs

World-renowned Te Waikoropupu (Pupu) Springs in Golden Bay have been put off-limits to divers and swimmers to protect the waters from the invasive algae didymo.

The Department of Conservation (DoC) is banning people from having contact with or putting any equipment into the springs. The ban applies to all waters within the Pupu Springs Scenic Reserve that is managed by DoC.

DoC Golden Bay area manager John Mason said Pupu Springs were internationally significant and had high ecological value, and it was "of utmost importance" to protect them.

They are the largest cold-water springs in the Southern Hemisphere, with water clarity said to be second only to Antarctica's Weddell Sea.

The move follows news last week that the highly invasive didymo, or rocksnot, had been found in the Waitaki River in South Canterbury.

That find prompted concerns from state electricity generator Meridian Energy over the algae's likely effect on its hydroelectric canals and fears from salmon farmers upstream in the Mackenzie Basin for the future of their multimillion-dollar industry.

Canterbury's regional council, Environment Canterbury (ECan), is due to meet in Christchurch today to discuss the implications of the latest find and co-ordinate further responses to the algae threat.

Mr Mason said the springs would be closed "until we find some way of eradicating didymo".

"It's now in five catchments in the South Island and we've decided it's better to take a precautionary approach and ensure it doesn't get here."

Mr Mason said DoC would never forgive itself if didymo was found in the springs in the future and the department had done nothing to prevent it.

With between 50,000 and 70,000 visitors a year, the springs were the most visited attraction in Golden Bay.

"Given the springs and their uniqueness, we think a precautionary approach is well-justified," Mr Mason said.

The movement of people and gear such as wetsuits between water bodies risked spreading didymo.

"Even though people are being told to clean and disinfect their gear to prevent the spread of didymo and other aquatic pests, there can be no way of knowing people have followed the necessary cleaning procedures," Mr Mason said.

"Didymo is not always visible and it only takes one microscopic fragment to infest an unaffected water body with it."

The only sure way of preventing didymo being carried into the pristine springs was to close the waters to contact by people or equipment.

Mr Mason said DoC appreciated there might be some disappointment at closing the springs, but they were exceptional and the department had to take effective measures to safeguard them.

Te Waikoropupu Springs are noted for their diversity of submerged mosses and liverworts that thrive in the cool water, including an endemic moss found nowhere else.

A total of 43 native invertebrate species have been found in the springs, half of which may exist only there.

The Main Spring and Dancing Sands pool have many types of native aquatic plants. Native fish in the springs include a healthy population of giant kokopu, an endangered species.

Mr Mason said Golden Bay iwi Manawhenua ki Mohua had been consulted over the decision to close the springs and supported the move.

- NZPA